JPS61294473A - Electrostatic recording device - Google Patents

Abstract

PURPOSE:To fix satisfactorily an address, etc. to an envelope, etc. by providing the second fixing device for fixing a transfer material formed by superposing plural sheets of paper such as the envelope, etc., separately from a fixing device. CONSTITUTION:The second fixing device 102 for fixing the envelope, etc. is provided on a carrying path 101 made to branch by a path switching gate 100 from on the way of a transfer material carrying path for reaching the original heating roller fixing device from a transfer position 5 running along a photosensitive drum 7, and a discharge paper tray 103 is provided on its discharge port. In case when the envelope is used as a transfer material, it is detected by installing a paper feed cassette, the gate 100 is switched to a position for guiding the transfer material to the second fixing device 102, and the envelope discharged from a transfer part 5 passes through the carrying path 101, is carried through the carrying path in the second fixing device 102, a heat source from a flash lamp 104 is irradiated and fixed, and the envelope is discharged to the discharge paper tray 103 from a discharge roller. Accordingly, an address can be recorded directly to the envelope by an electrostatic recording device.

Description

[Detailed description of the invention] Technical field The present invention relates to electrostatic recording devices.

BACKGROUND ART Recently, as a means of writing addresses on a large number of envelopes, it has become common practice to read out a large number of address information stored in a storage means as electrical signals, manually input them to a printer, and print characters corresponding to the electrical signals. Became. Printers print at very high speeds, but the paper that can be printed on is usually limited to paper that is about the same thickness as ordinary recording paper, and paper that has multiple sheets stacked on top of each other, such as envelopes, and that is difficult to deform freely. It is difficult to write addresses on envelopes, and the common practice is to print on plain paper using a printer, cut it to an appropriate size, and paste it on the envelope, which hinders work efficiency. There were some difficulties.

An electrostatic recording device that forms a toner image corresponding to an information signal on a photoconductor, transfers it to transfer paper, and heats the transferred toner image to fuse and fix it to the transfer paper, similar to a laser printer. There are problems when printing on envelopes made of multiple sheets of paper in a bag shape, multiple sheets of paper bound together, and paper of considerable thickness.

One of them is the problem of transferring toner images on the photoreceptor.

Transfer of a toner image is usually performed by charging the transfer paper from the back side of the transfer surface using a corona discharger and electrostatically adhering the toner image on the photoreceptor to the surface of the transfer paper. When stacking multiple sheets of paper, not only does the total thickness of the paper become thicker, but there is also a layer of air between each sheet of paper, which makes it difficult for the toner to reach the surface to be transferred to the required charge. This means that defects will occur. The same applies when the thickness of the transfer material is considerably thick.

Another problem is that when using a heating roller fixing device that has a roller pair consisting of a heating roller and a pressure roller that are in pressure contact with each other as a fixing device, there is a problem between the pair of rollers that are in pressure contact with each other with a fixing pressure suitable for fixing plain paper. When an envelope is passed through, there are disadvantages in that the pressure causes wrinkles and the air inside the envelope accumulates at the rear end, causing the envelope to burst. Also, the tip is difficult to get caught in the nip of the roller, which may cause a timing shift. Furthermore, a difference occurs between the temperature of the paper on the side that contacts the heat fixing roller and the temperature of the paper on the side that contacts the pressure roller.
The seal and cylinder are distorted due to the difference in the amount of thermal expansion, and when this is pressurized, wrinkles and creases are formed.

Purpose The present invention solves the above-mentioned problems regarding fixing when recording on envelopes or transfer materials made of bound sheets of paper using an electrostatic recording device. The purpose is to provide a good device for recording addresses, etc.

Structure In order to achieve the above object, the present invention provides an electrostatic recording apparatus having a heating roller fixing device that performs fixing through a transfer material carrying an unfixed toner image on a pair of rollers including a heating roller and a pressure roller. The present invention is characterized in that a second fixing device for fixing a transfer material formed by stacking a plurality of sheets of paper such as an envelope is provided separately from the original fixing device.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a diagram showing a schematic configuration of an example of a laser printer.

This laser printer consists of a lower unit 1 and an upper unit 2. Both units are pivoted to each other at the back side when viewed from the operator, and the front side opens wide like the head of a lion dancer. . The chain line A-A in FIG. 1 is the boundary line between the upper and lower units, and the lower unit 1 accommodates the paper feed section 4 for the transfer paper 3, the transfer device 5, and the paper conveyance section 6 of the transfer device. ing.

L! -L2/SOLLQL-L+Balance Unit 7-*O2/Sequence port 11 that controls the electrostatic recording unit consisting of 8, toner tank 9, and fixing device 10, and a sequence port 11 that controls the sequence of the machine, and a sequence port 11 that controls the sequence of the machine There are two electrical boards of the controller 12 that controls the interface and character generation, a laser optical system unit 13, a power supply 14 that supplies power to all the devices, electrical components such as the main motor 15, and a reversing paper ejection unit 16. It is accommodated. The cover 18 of the upper unit 2 is removable, and its upper surface also serves as a paper discharge tray 19 for the transferred paper discharged from the reversal paper discharge unit 16.

The fixing device 10 includes a fixing roller 21 having a heater 2o inside.
The heating roller fixing device includes a pressure roller 22 and a pressure roller 22 that is in pressure contact with the heat roller fixing device.

In laser printers that can use envelopes, etc. as transfer materials, the fusing pressure between the fusing roller and the pressure roller is variable, and the fusing pressure when fusing envelopes, etc. is the same as when fusing plain paper. The fixing pressure is set to be lower than the fixing pressure of

Furthermore, as shown in Figure 2, not only is the fusing pressure of the envelope lower than that of plain paper, but also the fusing pressure at the front and rear edges of the envelope is lower than the fusing pressure between the effective image fixing area of the entire length of the envelope. It is desirable to apply an even lower pressure (2) at the ends. By doing this, the front end of the envelope is easily caught in the nip between both rollers, and the pressure is low at the rear end where the distortion at the edge of the bag does not escape, so there is no strain and wrinkles occur. It is possible to pass through the roller pair without any problems.

The change in fixing pressure described above is achieved, for example, by a mechanism as shown in FIG. In FIG. 5, the fixing roller 21
is pivotally supported at a fixed position in the upper unit 2 of the recording apparatus, and the pressure row 222 is supported by levers 23 at both ends. One end of the lever 23 is swingably supported by a pin fixed to the upper unit 2, and the other end is supported by one end of a lever 25, which swings around a fulcrum 24 fixed to the lower unit. When the upper and lower units 1.2 are closed, the lever 26 is pushed upward by the compression spring 27, and both rollers 21 and 22 are pressurized. . Lever 2
The left end of 5 is engaged with a cam 31 which is rotated by a step motor 28 via a worm 29 and a worm wheel 3°. Therefore, the compression spring 27 is compressed according to the amount of protrusion of the cam 61 at the engagement point, and as a result, the fixing pressure between both rollers changes. As shown in FIG. 4, the position A of the minimum protrusion amount of the cam 31, the position C of the maximum protrusion amount, and the intermediate position B
The fixing pressures were set to be the values of ■, ■, and ■ in FIG. 2, respectively. Therefore, for plain paper, hold the cam at position C, for envelopes, hold the cam at position A at the front and rear ends, and at position ■ in the effective image fixing area.
By controlling the rotation of the cam, changes in fixing pressure as shown in FIG. 2 can be obtained.

The above control is performed as follows.

As a means for detecting whether the transfer material used is plain paper or an envelope, for example, as shown in FIG. In order to detect the size, a size detection tongue 53 is fixed to the front end of the cassette and is integrally provided with a side fence 51 that is moved according to the width of the transfer material, and protrudes through a slit 52 provided at the front end of the cassette. An envelope detection tongue piece 54 is provided, and when the envelope cassette 50 is installed in the apparatus, the envelope detection tongue piece 54 is detected by a sensor 55 provided at a corresponding position in the apparatus. There is. The plain paper cassette 56 has a side fence 5.
Although a size detection tongue piece 53 that is displaced together with the size detection tongue piece 53 is provided, an envelope detection tongue piece 54 is not provided, so that it is possible to easily detect whether or not it is an envelope. The size of the envelope is also detected.

The detection result of the sensor 55 is sent to the CPU 57 as shown in FIG.
is entered, processed, envelope mode is selected, and the third
As shown in the figure, from the time when the leading edge of the envelope is detected by the sensor S provided upstream of the fixing device, the stepping motor 28
control the rotational position of the The sensor S may also be provided on the paper conveyance path for other purposes. As a result, in envelope mode, the fusing pressure is lower than for plain paper, so
It is desirable to increase the temperature of the heater 20 via the relay 58 to ensure the fixing ability.

In addition, when transferring the toner image formed on the photoreceptor drum to an envelope, the transferred image is charged via multiple sheets of paper and an air layer, so power is required to charge the toner image to a predetermined charge. Controls the puck 59 to increase the transfer current of the transfer charger 5. Further, in the case of envelope mode, the data writing timing is instructed to the controller 12 based on the envelope size and paper feed timing, and the display unit 60 indicates the envelope mode. or plain paper mode.

The switching of the fixing pressure between the envelope mode and the plain paper mode may be performed manually by an operator instead of being controlled by displacing a cam with a stepping motor via the CPU based on a transfer material type detection signal. In that case, the cam 61 (7th (2)) provided at the same position as the cam 31 in FIG.
As shown in the figure, the displacement can be made by the operator turning a knob 62 provided on the outside of the device housing.

As shown in FIG. 9, around the knob 62, it is desirable to indicate the position of the knob as "envelope" or "plain paper". In this case, it is not possible to further reduce the pressure at the front and rear ends of the envelope by hand, so the cam position is set to A as shown in Figure 10.
, B2 point to switch between plain paper and envelopes, and at the same time, in the envelope mode where the fixing pressure is low, it is preferable to switch the heater to increase the constant wetness. Also, as shown in Figure 7,
The movement of the cam 61 turns on and off a switch 63, which serves as an envelope mode sensor, and inputs data to the host machine. Note that when in envelope mode, the fixing roller 21
In the case of a fixing device in which the heater 20 is installed only in the toner, the toner can be melted, but the heat is difficult to transfer to the pressure roller side, so the amount of thermal expansion differs between the top and bottom surfaces of envelopes, etc., causing distortion. If pressure is applied, wrinkles will form. Therefore, as shown in FIG. 11, a heater 20 may be provided not only for the fixing roller 21 but also for the pressure roller 22 so that both generate heat in the envelope mode.

In addition, it is difficult to bend an envelope, and it is not appropriate to make a U-turn after fixing and eject the paper to the ejection tray 19 at the top of the device. Therefore, as shown in FIG. It is preferable that the tray 66 is provided with a switching claw 65 for switching the conveying direction to a direction in which the sheet can be discharged, and a paper discharge receiver for receiving the paper discharged in that direction so that the tray 66 can be folded. FIG. 12(,) shows the envelope mode in which the tray 66 is used for this paper discharge tray, and FIG. 12(b) shows the state in which it is folded. It is preferable that this switching is performed under the control of the CPU by detecting the detection protrusion 56 of the paper feed cassette, or in conjunction with the rotation of the knob 62 shown in FIGS. 8 and 9.

In the example explained so far, the fixing device when using envelopes etc. as the transfer material is the fixing device for fixing plain paper.
Although it has been used with different fixing conditions, below, based on the present invention, a fixing device suitable for fixing envelopes, etc. is provided separately from the fixing device originally used for plain paper. An electrostatic recording device will be described.

In the embodiment shown in FIG. 13, an envelope or the like is fixed on a conveying path 101 branched by a path switching gate 100 from the middle of the transfer material conveying path from the transfer position 5 along the photosensitive drum 7 to the original heating roller fixing device. A second fixing device 102 is provided, and a paper discharge tray 106 is provided at its discharge port. The second fixing device 102 uses a flash lamp 104 on the surface of the transfer material being conveyed at a constant speed.
It is a flash fixing device that irradiates heat rays to melt the toner and fuse it to the transfer material.

When an envelope is used as the transfer material, it is detected by installing the paper feed cassette as described above, and the gate 100 is switched to the position where the transfer material is guided to the second fixing device 102, and the paper is removed from the transfer unit 5. The envelope that has come out is conveyed through a conveyance path 101 and then through a conveyance path in a second fixing device 102, and is irradiated with heat rays from a flash lamp 104 to be fixed, and is then discharged from a discharge roller to a paper discharge tray 103.

The flash fixing device does not apply any pressure to the transfer material because the member does not touch the transfer surface, and the transfer material is conveyed in a straight line, so it is suitable for fixing envelopes and the like. The envelope discharged from the fixing device 102 is generally discharged out of the machine in that direction.

In the embodiment shown in FIG. 14, the second fixing device is a heating roller fixing device. In that case, the fixing pressure and fixing temperature conditions may be as explained earlier in FIG. 2 or FIG. 10, and therefore the structure may be the same as in FIG. do. Ta! and the second fixing device 10
Since fixing of plain paper is not performed in 2, the number of cam positions is small, and the cam is not necessary in some cases.

FIG. 14 shows a fixing device without a cam.

Since its effect is self-evident, further explanation will be withheld.

In the embodiment shown in FIG. 15, the fixing device 1 for envelopes etc.
05 is removably attached so that the carry-in port is connected to a path that branches off from the transfer material discharge path 6 from the original fixing device 10 in the recording apparatus main body and opens to the outside of the apparatus. When the second fixing device 105 is installed, a lever 107 that is biased clockwise by a compression spring 106 moves into the recording apparatus main body from the second fixing device 105, and the pressure roller 22 of the original fixing device is pressed against the spring 27. The upper surface of the lever 25 that is being pushed up is pressed with the force of , and the pressing force of the lever 25 is reduced.

As a result, the fixing pressure between the fixing roller 21 and the pressure roller 22 is almost completely released, and becomes a pressure that only slightly conveys and guides the transfer material. Furthermore, the conveyance path 6 leading to the paper output tray at the top of the recording apparatus is blocked by a protrusion 108 inserted into the recording apparatus main body from the upper part of the paper insertion opening of the second fixing apparatus 105, and the conveyance path to the fixing apparatus 105 is opened. be done. The fixing means of the second fixing device 105 is a flash fixing device, and a paper discharge tray 103 is connected to the outside of its discharge port.

Therefore, the transfer material such as an envelope conveyed from the transfer section is conveyed with almost no pressure by the pair of rollers 21 and 22 of the fixing device 10, enters the second fixing device 105, and is fixed by a flash lamp. , and are discharged onto the paper discharge tray 106.

In the embodiment shown in FIG. 16, the fixing means has the same structure as the heat roller fixing device shown in FIG. 3, except that the fixing pressure on the front and rear edges of the paper and the fixing pressure on other parts can be changed. is similar to the embodiment shown in FIG.

Its effect is self-evident from the explanation given so far.

In the embodiment shown in FIG. 15.16, the original fixing device 10
When using the second fixing device, the second fixing device must be removed.

Effects As described above, according to the present invention, a toner image transferred by an electrostatic recording device to a transfer material made of a plurality of overlapping sheets of paper, such as an envelope, can be fixed well.
It becomes possible to record addresses directly on envelopes using an electrostatic recording device, and a remarkable effect can be obtained in improving office efficiency.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the overall schematic configuration of an electrostatic recording device to which the present invention is applied, Fig. 2 is a curve diagram showing the fixing pressure when fixing plain paper and envelopes, and Fig. 3 is a variable fixing pressure Figure 4 is a curve diagram showing the relationship between cam displacement and fixing pressure shown in Figure 3, and Figures 5 (a) and 5 (b) are for envelopes and normal paper feed, respectively. FIG. 6 is a perspective view of an example of a cassette, FIG. 6 is a control block diagram of the device, FIG. 7 is a front view of another example of a fixing device with variable fixing pressure, FIG. 8 is a front view of its housing, and FIG. Enlarged front view of the vicinity of the knob, No. 10
The figure is a curve diagram showing the relationship between the displacement of the cam, the fixing pressure, and the fixing temperature, FIG. 11 is a front view showing yet another example of the fixing device, and FIG. 12 is an example of the paper ejection path after fixing. In the cross-sectional view, (,) shows the envelope output tray open, and (b)
13 is a diagram showing a closed state, and FIGS. 13 to 16 are sectional views showing embodiments of the present invention. 1.2... Electrostatic recording device 6... Transfer material 5... Transfer section 10... Original fixing device 20...
Heat source 21... Fixing roller 22... Pressure roller 100... Switching gate 102.105.
...Second fixing device 103...Discharge tray 106, 107...Pressure release means 108...Entrance opening means Figure 9 Figure 8 Figure 1 IO Figure 11 Figure 13 Figure 14

Claims (9)

[Claims] (1) In an electrostatic recording device that has a heat roller fixing device that performs fixing by passing an unfixed toner image through a transfer material between a pair of rollers that are in pressure contact with each other and have a heat source inside one of them, an electrostatic recording device that has . An electrostatic recording device characterized by being provided with a second fixing device for fixing a transfer material formed by stacking a plurality of sheets of paper. (2) The above-mentioned second fixing device is provided in a conveyance path branched by a gate from the transfer material conveyance path leading from the toner image transfer section to the above-mentioned original fixing device. The electrostatic recording device according to item 1. (3) The electrostatic recording device according to claim 2, wherein the second fixing device is a flash fixing device. (4) The second fixing device is a heat roller fixed device, and the fixing pressure thereof is set to a lower value than the fixing pressure for plain paper. Electrostatic recording device. (5) The electrostatic recording device according to claim 4, wherein the fixing pressure of the second fixing device is lower at the front and rear ends of the transfer material than at other parts. (6) The above-mentioned second fixing device can be selectively attached to and removed from a path branching from the transfer material conveyance path from the above-mentioned original fixing device, and by fixing this, the above-mentioned original fixing device can be At the same time as the fixing pressure of the roller pair of the device is released,
2. The electrostatic recording device according to claim 1, wherein the transfer material conveyance path from the fixing device is switched to a path toward the second fixing device. (7) The electrostatic recording device according to claim 6, wherein the second fixing device is a flash fixing device. (8) The second fixing device is a heat roller fixing device, and the fixing pressure thereof is set to a lower value than the fixing pressure for plain paper. Electrostatic recording device. (9) The electrostatic recording device according to claim 8, wherein the fixing pressure of the second fixing device is lower at the front and rear ends of the transfer material than at other parts.